This invention relates to jet engines and in particular to the production of thrust components at right angles to the main thrust direction of the engine. The invention also relates to jet aircraft employing air cushion takeoff and landing systems and particularly to the directional control of such aircraft when being taxied and during that part of the takeoff or landing run where the speed is below the speed at which the aerodynamic control surfaces are effective.
Since aircraft equipped with air cushion systems have no wheels, the usual methods of low speed directional control on the ground, such as a steerable nose wheel of differential braking of the main wheels, are not available. One steering method that has been used employs roll induced yaw to control the aircraft direction indirectly. Rotation of the aircraft about its roll axis is accomplished in this method by small wing tip thrusters which operate in opposite directions to produce the desired roll moment. Each thruster has upwardly directed and downwardly directed output channels and is supplied with compressed air from a single conduit extending through the wing from a suitable source of pressurized air in the aircraft, such as the jet engine compressor. Remotely controlled means are provided at each thruster to switch the air flow to either the upward channel or the downward channel to control the direction of the roll moment.